1. Field of the Invention
This invention relates broadly to skin rejuvenation. More particularly, this invention relates to methods, devices, techniques and materials for skin rejuvenation.
2. State of the Art
There are many known techniques for skin rejuvenation (the removal or lessening of the appearance of wrinkles and/or folds on the skin and/or sagging skin) including surgical skin tightening, less-evasive subcutaneous skin tightening and dermal fillers.
As part of surgical skin tightening, the skin is incised in an area that is adjacent the wrinkled skin. Additional skin peeling is performed. Finally, the skin is tightened and the excess is cut off. Such techniques are disadvantageous due to the high trauma involved and a high risk of post-operative adverse side effects (such as hematomas and scar complications).
Less evasive subcutaneous skin tightening employs a surgical thread to gather and tighten wrinkled or sagging skin. For example, European Patent No. 1075843 discloses the use of a barbed surgical thread in cosmetic applications. The barbs of the thread are oriented in a direction opposite that of thread pull. The thread is made of metallic, polymeric or biological materials. This type of thread, made from polypropylene, is used commercially under the name FeatherLift™ to provide skin tightening. The thread is inserted under the skin generally perpendicular to and extending away from the wrinkles or sagging skin. The barbs at one end of the thread anchor themselves to the skin at or near the winkles or sagging area. The other end of the thread is pulled tight and tied to tissue (e.g., the facia of the head), thereby gathering and tightening the skin in a manner that lessens the appearance of the wrinkles or sagging skin.
A dermal filler is a biocompatible material that is injected into the skin. These fillers include collagen, silicone, colloidal microspheres of PMMA, colloidal microspheres of PTFE (Teflon®) and colloidal hydroxyapatite. Collagen injections, which are most popular, suffer from the collagen degrading with time, resulting in numerous visits to the plastic surgeon for re-injection. Furthermore, collagen is hypoallergenic and approximately seven percent of the population suffers from these allergies. In addition, collagen from bovine origin can carry prions from mad cow disease which can be deadly to the patient. Silicone as well as PMMA and Teflon microspheres do not degrade, however they all do tend to migrate from the injection site. The microspheres are at times found as far away as the lymph nodes. Hydroxysapatite injections are forerunners to bone formation and tend to harden with time. More recently, dermal fillers such as Restylane® (hyaluronic acid), Hylaform®) (hyaluronic acid) and Sculptra™ (poly-L-lactic acid) have been introduced for cosmetic applications. All of these fillers are helpful but temporary in nature. Moreover, if injected incorrectly, they are non-removable and therefore cannot be corrected.